Image Sensors in Tfa Technology - Status and Future Trends

1998 ◽  
Vol 507 ◽  
Author(s):  
M. Böhm ◽  
F. Blecher ◽  
A. Eckhardt ◽  
K. Seibel ◽  
B. Schneider ◽  
...  
Keyword(s):  
Thin Film ◽  
Spectral Sensitivity ◽  
Dark Current ◽  
Transient Behavior ◽  
Image Sensors ◽  
Cell Design ◽  
Future Trends ◽  
Temperature Influence ◽  
Future Perspectives ◽  
Research Results

ABSTRACTImage sensors in TFA (Thin Film on ASIC) technology have been successfully fabricated and tested. This paper provides a survey of TFA research results so far and outlines future perspectives. The properties of different a-Si:H b/w and color thin film detectors are evaluated, including spectral sensitivity, dark current, temperature influence and transient behavior. Furthermore several TFA prototypes and emerging concepts are presented, ranging from a simple one-transistor cell design to a locally autoadaptive sensor.

scholarly journals Image Sensors Based on Thin-film on CMOS Technology: Additional Leakage Currents due to Vertical Integration of the a-Si:H Diodes

2006 ◽  
Vol 910 ◽  
Author(s):  
Clement Miazza ◽  
N. Wyrsch ◽  
G. Choong ◽  
S. Dunand ◽  
C. Ballif ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Vertical Integration ◽  
Dark Current ◽  
Cmos Technology ◽  
Image Sensors ◽  
Dark Current Density ◽  
Leakage Currents ◽  
Planar Configuration ◽  
Cmos Chip

AbstractImage sensors based on thin-film on CMOS technology (TFC) have been developed. In this approach, amorphous silicon (a-Si:H) detectors are vertically integrated on top of a CMOS readout chip so as to form monolithic image sensors. In order to reduce as far as possible the dark current density (Jdark) of the TFC sensors, we have focused on analyzing and understanding the behavior of Jdark in this type of detectors. Edge effects along the periphery and at the corners of the pixel, due to the non planar configuration of the vertically integrated photodiodes, are found to be responsible for an increase of the dark current. A new and adapted solution for the minimization of Jdark is proposed, which combines the use of a metal-i-p a-Si:H diode configuration with a deposition on top of an unpassivated CMOS chip. Values of Jdark as low as 12 pA/cm2 at a reverse polarization of V = -1 V are measured on such TFC sensors.

Improved Electrical Properties of Ga2O3:Sn/CIGS Hetero-Junction Photoconductor

2014 ◽  
Vol 1635 ◽  
pp. 83-88
Author(s):  
Kenji Kikuchi ◽  
Shigeyuki Imura ◽  
Kazunori Miyakawa ◽  
Hiroshi Ohtake ◽  
Misao Kubota ◽  
...  
Keyword(s):  
Thin Film ◽  
Quantum Efficiency ◽  
Repetition Rate ◽  
Dark Current ◽  
Carrier Density ◽  
High Efficiency ◽  
Visible Region ◽  
Laser Frequency ◽  
Image Sensors ◽  
High Quantum Efficiency

ABSTRACTWe examined the potential application of CuIn1-xGaxSe1-ySy (CIGS) film for visible light image sensors. CIGS chalcopyrite semiconductors, which are representative of high efficiency thin film solar cells, have both a high absorption coefficient and high quantum efficiency. However, their dark current is too high for image sensors. In this study, we applied gallium oxide (Ga2O3) as a hole-blocking layer for CIGS thin film to reduce the dark current. The dark current of this hetero-junction was 10-9 A/cm2 at less than 7 V. Moreover, an avalanche multiplication phenomenon was observed at an applied voltage of over 8 V. However, this structure had sensitivity only in the ultraviolet light region due to the much lower carrier density of the Ga2O3 layer. We therefore used a tin-doped Ga2O3 (Ga2O3:Sn) layer deposited by pulsed laser deposition (PLD) for the n-type layer to increase the carrier density. The sensitivity of the visible region was observed in the Ga2O3:Sn/CIGS hetero-junction. We also investigated the influence of the laser frequency of the PLD on the transmittance of Ga2O3:Sn and the quantum efficiency of this hetero-junction. Ga2O3:Sn film deposited at a 0.1-Hz laser repetition rate had higher transmittance than at a 10-Hz repetition rate. The Ga2O3:Sn/CIGS hetero-junction also had a higher quantum efficiency with the lower rate (50%) than with the higher rate (30%).

Electrical Properties of Ga2O3:Sn/CIGS Hetero-junction

2014 ◽  
Vol 1603 ◽  
Author(s):  
Kenji Kikuchi ◽  
Shigeyuki Imura ◽  
Kazunori Miyakawa ◽  
Misao Kubota ◽  
Eiji Ohta
Keyword(s):  
Thin Film ◽  
Visible Light ◽  
Dark Current ◽  
Carrier Density ◽  
High Speed ◽  
Depletion Region ◽  
Image Sensors ◽  
Frame Rate ◽  
Semiconductor Layer ◽  
High Quantum Efficiency

ABSTRACTThere is an increased need for highly sensitive imaging devices to develop high resolution and high speed image sensors. Incident light intensity per pixel of image sensors is getting lower because the pixel resolution and frame rate of image sensors are becoming higher. We investigated the feasibility of using a photoconductor with tin-doped gallium oxide (Ga2O3:Sn)/Cu(In,Ga)Se2 (CIGS) hetero-junction for visible light image sensors. CIGS chalcopyrite thin films have great potential for improving the sensitivity of image sensors and CIGS chalcopyrite semiconductors have both a high absorption coefficient and high quantum efficiency. Moreover, the band gap can be adjusted for visible light. We applied Ga2O3 as an n-type semiconductor layer and a hole-blocking layer to CIGS thin film to reduce the dark current. The experimental results revealed that dark current was drastically reduced due to the application of Ga2O3 thin film, and an avalanche multiplication phenomenon was observed at an applied voltage of over 6 V. However, non-doped Ga2O3/CIGS hetero-junction only had sensitivity in the ultraviolet light region because their depletion region was almost completely spread throughout the Ga2O3 layer due to the low carrier density of the Ga2O3 layer. Therefore, we used Ga2O3:Sn for the n-type layer to increase carrier density. As a result, the depletion region shifted to the CIGS film and the cells had sensitivity in all visible regions. These results indicate that Ga2O3:Sn/CIGS hetero-junction are feasible for visible light photoconductors.

Effect of transient behavior on off-state current in poly-Si junctionless nanowire thin-film transistor

2020 ◽  
Vol 59 (12) ◽  
pp. 126503
Author(s):  
Tsung-Kuei Kang ◽  
Che-Fu Hsu ◽  
Han-Wen Liu ◽  
Feng-Tso Chien ◽  
Cheng-Li Lin
Keyword(s):  
Thin Film ◽  
Thin Film Transistor ◽  
Transient Behavior

Design of Ultra Low Temperature Pressure and Temperature Sensor Structure

2011 ◽  
Vol 80-81 ◽  
pp. 693-697
Author(s):  
Chang Hong Ji ◽  
Bin Zhen Zhang ◽  
Jian Zhang ◽  
Xiang Hong Li ◽  
Jian Lin Liu
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Pressure Sensor ◽  
Temperature Sensor ◽  
Elastic Membrane ◽  
Temperature Influence ◽  
Sensor Sensitivity ◽  
Piezoresistive Pressure Sensor ◽  
Sensor Structure

In order to measure the pressure in the ultra-low temperature condition, the structure of ultra-low temperature piezoresistive pressure sensor is designed. Polysilicon nanometer thin film is used as a varistor according to its temperature and piezoresistive characteristics. The effect of the dimensions of silicon elastic membrane for the sensor sensitivity and the strain dimensions of the elastic membrane are analyzed, then layout position of resistances is arranged. The package structure of pressure sensor is designed. Meanwhile, a low-temperature sensor is designed to compensate the temperature influence to the pressure sensor.

scholarly journals A review on thin films, conducting polymers as sensor devices

2022 ◽  
Author(s):  
E.L. Veera Prabakaran ◽  
K Senthil Vadivu ◽  
B Mouli Prasanth
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Environmental Conditions ◽  
Future Research ◽  
Physical Parameters ◽  
Research Needs ◽  
Future Perspectives ◽  
Thin Film Technology ◽  
Thin Film Sensors ◽  
Sensor Devices

Abstract Thin film sensors are used to monitor environmental conditions by measuring the physical parameters. By using thin film technology, the sensors are capable of conducting precise measurements. Moreover, the measurements are stable and dependable. Furthermore, inexpensive sensor devices can be produced. In this paper, thin film technology for the design and fabrication of sensors that are used in various applications is reviewed. Further, the applications of thin film sensors in the fields of biomedical, energy harvesting, optical, and corrosion applications are also presented. From the review, the future research needs and future perspectives are identified and discussed.

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